Improvement in slide-valves



Ntra STATES Parar Orificec JOHN O. WOODHEAD, OF PITTSBURG, PENNSYLVANIA.

Specifica-tion forming part of Letters Patent No. ,l 12,002, datedFebruary 2l, 1871; antedatcd y February 18, 1871.

.To @ZZ whom it may concern:

Be it known that I, JOHN C. WooDHEAD, of Pittsburg, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvements in Balance Slide- Valves; and I do hereby declarethat the following is a full, clear, and exact description thereof,reference being had to the accompanying drawings, and to the letters ofreference marked thereon, which form a part of this specification.

'Ihis invention relates to that class of valves known as balanceslide-valvesg7 and it consists in constructing the valve with a centralcasing having a diaphragm, and employing` two valves in connection withthe same, as will be fully described hereinafter.

In the drawing a plan view or" my invention shown.

To enable others skilled in the art to make and use my invention, I willnow proceed to describe fully its construction and manner of operation.

A and B represent two vertical casings, which are provided with ports oropenings A A2 A3 B BZ B3 in the sides, as shown in the drawing. Theseopenings pass through said casing in such manner as to correspond at thebase with the ordinary openings or parts in any ordinary form ofvalve-seat. A plate is placed over said casings and secured thereto inany proper manner.

E represents a central casing, which is preferably used with thediaphragm E.

E2 E3 represent valves, which are provided with central openings withthe ordinary relative size to the other parts, which act as the exhaustof an ordinary slide-valvc.

All the parts are so arranged relatively to each other that when thevalves are reciprocated steam will be admitted sidewise into any oftheside openings oi' casings A and B,which may be exposed. The steamtraversing through said openings will pass through the ordinarycylinder-ports and be used in the ordinary manner. As the upper parts ofthe valves press against the casing-plate no pressure of steam can bearupon the same, and the valve is thus left free to move, untrammeled byany baclepressure. The action of exhausting is not different from thatperformed in ordinary cylinders, except that the steam passes throughthe several exhaust-ports of the chambers.

Having thus fully described my invention, what I claim as new, anddesire to secure 4by Letters Patent of the United States, is-

The central casing, E, with diaphragm E', when employed in connectionwith two valves, as described, for the purpose set forth.

In testimony that I claim the foregoing as my own I affix my signaturein presence of two witnesses. Y

`JOHN C. WOODHEAD.

IVitnesses:

PERGIVAL BECKETT, BENJAMIN FALLows.

